Electric valve



' Aug. 12, 1924.

1,504,628 c. L. A. M. LEBLANC ELECTRIC VALVE Filed Dec. 16 1920 3Shuts-Sheet 1 d l l ljl l l Augg 12 1924. 1,504,628

c. L. A. M. LEBLANC ELECTRI C VALVE Filed Dec. 16, 1920 3 Shoots-Sheet 2I l'u Aug, 12 v 3924:; 1 5043528 Fig.

Patented Aug. 12, 1924.

UNITED STATES PATENT OFFICE.

CHARLES LEONARD ARMAND MAURICE LEBLANC, OF PARIS, FRANCE, ASSIGNOR TOSOCIETE ANONYME POUR LEXPLOITATION DES PROCEDES MAURICE LEBLANC-VICKERS, F PARIS, FRANCE.

ELECTRIC VALVE.

Application filed December 16, 1920. Serial No. 431,221.

To all whom. it may concern-.-

Be it known that I, CHARLES LEONARD ARMANI) MAURICE LEBLANC, a citizenof the Republic of France, residing at 1 Boulevard 5 de Montmorency,Paris, Seine, France, have invented certain new and useful Improvementsin Electric Valves; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to lettersor figures of reference marked thereon, which form a part of thisspecification.

The present invention relates to electric valves, and has for its objectto provide an electric valve which serves for transforming continuouscurrent into'single or polyphase alternating currents of any frequencywhich may be varied as required.

It may also be used to transform alternating currents of a givenfrequency into alternating currents of any frequency which,

may likewise be varied at will.

The method of operation of the valve is based upon certain phenomenawhich have been observed by the applicants in connection, for example,with a three-electrode mercury vapour lamp, and to which furtherreference will be made later.

According to the invention the electric valve comprises a lamp withthree electrodes, namely anode, grid and cathode, of which the cathodeis maintained in a state of constant incandescence, the said lamp beingfilled with a gas or inert vapour instead of being entirely evacuated,so that the current may be transmitted from the anode to the cathode bymeans of the ions instead of being transmitted solely by the electronsemitted by the cathode, the grid being interposed between the anode andcathode as in the case of audions, the said valve being operated byinsulating the grid or by rendering it negative with relation to thecathode, by means of a switch which is opened or closed, therebypermitting the passage of current or cutting off the latter.

In order that the invention may be clearly understood it will now bedescribed with reference to which Fig. 1 shows a three-electrode mercuryvapor lamp.

Fig. 2 shows the variation of the current flowing from anode to cathodein the lamp Fig. 1 when alternating current is used.

Fig. 3 represents the value of a wave current which can be used in thelamp in order to obtain the same results as with alternating current.

Fig. 4 shows an arrangement for converting an alternating current of agiven frequency into a sin 'le-phase alternating current of any desirefrequency.

Fig. 5 shows six curves for the current values in the different circuitsof Fig. 4;.

Fig. 6 represents an arrangement of transformers having twooppositely-wound secondaries.

Fig. 7 shows'an arrangement for converting an alternating current of agiven frequency into an alternating current of lower frequency by theuse of the positive and negative half-Waves of the standard alternatingcurrent.

Fig. 8 shows an oscillator for converting continuous current intosingle-phase alternating current of very high frequency.

Fig. 9 shows. circuits for converting threephase current of standardfrequencies into polyphase alternating current whose frequencies can bevaried at will.

Referring now .to the drawings, a threeelectrode mercury vapour lampformed by a vertical vacuum tube A has an iron electrode B arranged atthe top, the mercury the accompanying drawings in cathode C beingdisposed at the bottom,

while at the centre a grid D of iron or tungsten, for example, separatesthe tube in two parts.

At F, in the immediate vicinity of the cathode, an auxiliary anode isarranged through which a continuous current, which is never interrupted,flows in order to maintain the surface of the mercury in a state ofincandescence when no current passes through the principal anode B. Asmall battery of accumulators G in conjunction with a self-inductioncoil E supplies the necessary current. Another battery I connectedbetween the cathode C and the grid D enables the latterto be renderednegative with relation to the'cathode.

By means of a switch J the grid may be connected to or disconnected fromthe battery, as desired.

Whether the grid is disconnected or not, a current can only flow throughthe lam by passing from the anode B to the catho e C, as the mass ofmercury can never operate as an anode.

If a source of electricity having a constant electromotive force whichis greater than 14 volts, and which tends to cause a current to flowfrom the anode B to the cathode is connected between these elements, itwill be observed that:

-1. If the switch J has previously been closed, the grid being negativein relation to the cathode, the electromotive force may be raisedconsiderably without any current fiowin 2. I the grid is disconnected, acurrent passes through the lamp the intensity of which can be measuredin amperes. I the grid circuit switch J is then closed, there passesthrough the circuit JI a shunt of the current flowing through the coil Ein the direction anode to cathode. Along the shunt circuit JI, thepotential decreases in the direction of the current, as is well known.It followsthat the grid D, located at the entrance of the shunt circuitJI, is of a higher potential than the end of said circult, that is tosay, the positive pole of the battery I, the potential of which is aproximately the same as that of the catho The id can, therefore, neverbecome negative relatively to the cathode. The action is as though theeffect of the battery I were neutralized.

' pp y,

If the source of constant electromotive force is replaced by analternating current a current will flow, still in the same direction,from the anode to the cathode as long as the grid is disconnected. Thiscurrent is interrupted as soon as the switch J is closed.

The variations in the intensity 1' of the current which flows from theanode to the cathode, as a function of the time t may be shown by meansof a curve such as that in Figure 2. The short interru tions aredetermined by the alternations of t e electromotive force. This lastfrequency may be as high as desired.-

he same results can also be obtained if the electromotive force isalways in the same direction, but drops invalue periodically below 14volts, as for exam 1e, when these variations can be represented as afunction of the time by the curve shown in Fig. 3.

Finally,-the action of the id does not cause the lamp to be extinguishedwhen a difierence of potential (at least 14 volts in the case of mercurylamp) is maintained between the anode and the cathode, but it preventsthe lamp from re-lighting when it is extinguished spontaneously.

In the two last cases if the frequency of variation of the electromotiveforce is greater than that provided by the successive opening andclosing of the switch J, the lamp operates similarly to a valve,allowing the current to flow or arresting it as the switch J is openedor closed. This manipulation, apart from entailing very little work,also permits a very high resistance to be imparted to the circuitcontaining the bat tery I, and the energy which it will have to supply,particularly when it is traversed by a current emanating from the anodeB, is entirel negligible.

Assuming in the first place that an electromotive force having afrequency a: is available and that it is desired to produce asingle-phase alternating current having a frequency will be had to theFi re 4.

n this arrangement K is the core of a transformer; the latter isprovided with two primary windings M and having the same number ofturns, but wound in opposite directions. There is only one secondawinding P which constitutes the source o f singlephase alternatingcurrent having the frequency 5. If a current of the same direction isallowed to flow through the circuits M and N in succession, the sameeffect is produced as when a current flows alternately in one directionand then in the other in the same rimar circuit.

In the circuits N are provided the small condensers Q,- Q, connected inshunt between their ends. The use of the said condensers is to beexplained as follows:

Considering the circuit M with reference to the lamp A, the circuit issupplied with an alternating current whose frequency is a and. which isto be reduced to the lower frequencfy (5; the lamp arrests the n ativewaves 0 this current due to its rectifying power, and only allows thepositive waves to pass, this action taking place only while the grid hasa positive charge, or as usually stated, when the valve is open. Thevalve second, and

23 during this time the original current prois in fact left open forduces in the circuit M, positive waves,

as shown on curve II, Fig. 5.

a zero value each time during Second.

The current thus flows times, and has {5 smaller than the first,recourse arrangement shown in' Ill Ill

turbing phenomena in the adjacent circuits N and P.

The current having the frequenc of q is divided up between the windingand the condenser Q; the latter becomes charged as the current flows,and then during the time in which the current is at zero, the

condenser discharges andsupplies current to the lamp A, instead ofproducing a succession of separate half-waves separated by empty spacesas shown in curve II, Fig. 5, the effect will be a continuous undulate'dcurve lasting for the time as shown in and I are connected to the otherpole of the source of supply. 1

' A rotating commutator is arranged at R havin a number of segmentsmounted on a ring All those of odd number are connected to one anotherand with a slip-ring T while all those of even number are also connectedto one another and to a slip-ring T The odd number segments areinsulated from the even number segments. Any form of motor may beemployed to cause the commutator to rotate at the required speed.

A fixed contact p presses against the ring S and is connected to thepole of the battery I which serves for charging the grids. Two otherfixed contacts 9 and g press against the slip-rings T and T and connectthem respectively to the grid of each lamp.

Under these conditions the two grids successively become negative (withrelation to the cathodes) and disconnected, one of the grids becomingnegative while the. other is disconnected.

In Figure 5 six curves I, II, III VI are shown. The curve I representsthe variations in the electromotive force of the alternating currenthaving the frequency a, as a function of the time, which is utilized forfeeding the valve; the curve II shows the variatlons in the intensity 5of the current which is distributed between the circuit M and itscondenser; while the curve IV shows the current variations 7' for theportion of this current which traverses the circuit M and which is notneutralized by the reaction of the condenser. The curves III and Vrepresent the corresponding current variations i and 7' in the circuitN. Finally, the curve VI shows, to another scale, the variations in thenumber of ampere turns nc) which the circuits M and N develop around themagnetic core of the transformer K. These last variations have afrequency 3 whichis entirely dependent upon the speed of the commutator.

Anlalternating current having the frequency 5 will therefore bedeveloped in the secondary circuit P.

It should be noted that the alternating current supply only furnishesenergy during half the time when it flows in a given direction, as maybe seen from the curve Fig. 2 and curves II and III, Fig. 5.

The source of alternating current may be made to operate continuously byemploying two groups of apparatus similar to thatshown in Figure 4.

For this purpose it suflices to allow this current supply to flowthrough the primary circuit U of a transformer V (F i 6) which has twosecondary circuits X and with the same number of turns but wound inopposite directions in order to make use of the positive and negativewaves of the alternatingrcurrent supply.

he terminals of the two secondary circuits XY will be connected at oneend to the cathodes of the four lamps in the two groups, while those atthe other end will be connected to the primary circuits M, N of thetransformer K for each group, as shown in Fig. 7.

@nly currents of the same direction can flow in these primary circuits MN. During the half-periods of odd number, corresponding to the positivewaves of the source of electromotive force for example, a current willflow through the secondary circuit X, and during the half-periods ofeven number, corresponding to the negative waves, a current will flow inthe secondary circuit Y. The source of su ply will thus be utilizedduring the who e time.

If the two groups of apparatus shown in Figure 7 are taken, they may bemade to produce currents having frequencies which are displaced by 1period.

For this purpose it is only necessary to mount the two comrnu tators forthese groups S T T and S, T, T on the same shaft in such a manner thatthe segments of the ring S are displaced by a half so out with relationto those of the rin S nder these conditions the flux variatlons develoed in the core of the transformers KK will displaced by a riod. If eachof them has only one secon ary circuit P, two-phase currents will becommon know edge that nothing is easier than to. produce two-phasecurrents by means of two cores formin the seat of the flux variationswhich are isplaced by one quarter eriod.

1th the arrangement shown in Fig. 7

which is probably the most desirable embodiment of the invention it ispossible however to transform a single-phase alternatingcurrent having afrequency a into sing e or polyphase alternating currents with a lowerfrequency (5, this latter frequency depending solely upon the speed ofthe commutator which only has to interrupt currents having an energywhich is practically zero.

It is only on very rare occasions that an opportunity is presented ofcarrying out a transformation of this kind but it is of interest, inview of the fact that, by applying the principles involved, it is veryeasy to transform a high tension continuous current into a single-phasealternating current, a good efficiency being obtained, on the conditionthat its frequency is made very high by means of the arrangement shownin Fig. 8 and on combining it with the arrangement shown in Fig. 7

A mercury vapour lamp 6 which requires no attention is connected inshunt in a circuit comprising:

1'. A resonator consisting of a condenser 0 and a self-induction coil (1tuned to produce the frequency a.

2. The primary circuit U of'a transformer V which as in the case of thatshown in Fig. 6 may have two secondary circuits X and Y.

A self-induction coil e capable of maintaining constant the intensity ofthe current which flows through it for the duration of the period isarranged in series in the continuous current circuit, adjoining theanode of the lamp. Finally, the available continuous current supply isconnected between the cathode C of t e lamp and the beginning of thecoil 0, so that it tends to cause current to pass from the anode to thecathode of the lamp.

The potential of the current must be siifiicient to enable the lamp tolight up. Then, if the energy stored up in t e condenser at the momentof lighting up is reater than that which willbe consumed in the circuitcontainin the resonator and the primary circuit U or the duration of theperiod 5 the current will be neutralized in the lamp and the latter willbe extinguished before the end of each period to be relighted by thecontinuous current supply at the beginning ofthe following period. Theoscillations will therefore be sustained naturally.

This system which was described in the French Patents No. 333,387 of the25th June 1903 and No.'333,516 of the 1st July 1903 period i tends tomake the latter very short, so that onl currents of very high frequencyare pro uced.

It is of advantage, however, to make the frequency a of shortdurationwith relation to the frequency [5 for the currents it is desired toproduce, and the continuous current which it will be necessary inpractice to transform into alternating-currents will always have a veryhigh tension.

In order, however, to transform a hi h tension continuous currentserving for t e long distance transmission of energy, into polyphasealternating-currents of the customary frequency which is variable atwill and of any tension, this continuous current is first transformedinto a single-phase alternating-current of very high frequency by meansof the arrangement in Fig. 8, the transformer V of this system being thesame as the transformer V for the arran ement shown in Fi 7, which isconnecte as in this case to t e valve system.

Another important problem is the followiriven three phase currents atthe customary frequency, 25 or 50 cycles, for example, it is desired totransform them into polyphasealternating-c'urrents the frequency ofwhich can be varied as desired but can attain a value equal to severalhundred periods forthe urpose of feeding an induction motor Whi as torun at a speed of several hundred revolutions per second.

This is the most complicated case. The alternating-currents at thecustomar frequency are first transformed into big tenslon continuouscurrent by means of a mercury vapour rectifier. This continuous currentis then transformed into single-phase alternating-current of very highfrequency. Finally, t e latter is transformed into high fr uencycurrents which it is desired to pro uce. For this purpose recourse ishad to the arrangement shown in Fig. 9.

The currents at the customary frequency feed the primary windings (1, 2,3) of a step-up transformer. The transformed currents are rectified bymeans of a mercuryv vapour rectifier 4 which is assumed to have sixanodes, two secondary windings being allotted to each core so as toenable the source of sup iv to work constantly, that is to say, to utiize the positive and negative waves of the current.

The continuous current supplied by the rectifier feeds a device similarto that shown in Fig. 8 combined with the valve shown in Fig. 7 whichproduces the arrangement shown in 9 which merely amounts to thesuperimposing of the preceding systems, like letters designating similarparts.

The four lamps of the arrangement shown in Fig. 7 have been replaced,however, b a single lamp provided with four anodes l located at the topof four extensions closed by four grids but having only one cathode. Notonly is this arrangement more simple but it is only necessary tomaintain one single cathode in a state of incandescence so that economyin working is obtained.

Even in the most complicated case, name- 7 1y, for an arrangementcarried out in accordance with that shown in Fig. 9 the materialrequired is appreciably reduced and the successive transformations areeffected with a ve high efiiciency.

The rectifier 4 and the lamp 1) are traversed by currents having atension of several thousand volts, in view of which the dropof potentialof 14 volts caused by the passage of the current through the lamps isnegligible. Similarly, only high tension currents, of a thousand voltsfor example, will be obtained in the lamp with four, anodes which servesas a valve.

As these lamps are only traversed by currents of low intensity they willbe of small size. Finally, the transformer V through which highfrequency currents pass and the transformers KK through which currentshaving frequencies considerably greater than the customary frequenciesflow, will be ve small with regard to their output, and will have a highefiiciency.

For the sake of simplicity 1t has been assumed that the'current for thelamp, which serves as a valve and that for charging the grids, isfurnished by accumulators. In practice these would be replaced by mnetos mounted on the commutator sha Finally, the latter may be replacedin certain instances by a small alternator.

With the arrangement shown in Fig. 1 a

valve is obtained which can open and close the circuit of analternating-current of any frequency, which may be employed as a switch.

By coupling similar valves and manipulating them successively in apredetermined order, a single-phase current having a very high frequencymay be transformed into single or polyphase currents of any frequencywhich may be varied as desired but which are always less than the first,and' of any desired potential.

The high frequency alternating-current may be produced by means of anoscillator fed by high tension continuous current. Means are thusavailable for transforming this continuous current into single orpolyphase alternating currents of any frequency variable at will and ofany potential.

Finally, this continuous current may be obtained by rectifiying thealternating-currents of the customa frequency by means of a rectifier.It is t us possible to transform these alternating-currents intocurrents of another frequency which can be varied as required.

It has been assumed in the preceding description that the incandescentcathode of the lamp serving as a valve, was formed by a mass of mercuryand that the fluid filling the lamp was mercury vapour. This arrangementpossesses the advantage that the cathode does notwear away in the courseof time, as it re-constructs itself. It can however be replaced by ametallic filament which is kept incandescent by the passa e of current,and the mercury vapour may e replaced by a fluid such as argon or neon,the molecules of which, when split up by the electrons emitted by thefilament, supply the ions necessary for the flow of current.

v What ll claim is 4 1. A frequency changing device comprising a pair ofpartial vacuum tubes each containing an anode, a grid, a cathode and afluid, whereby the current shall be transmitted by the ions, anauxiliary anode for maintaining the cathode constantly in anincandescent state, means for intermittently imparting to the said grida constant negative potential, a transformer having a single secondarywinding and a pair of equal and oppositely wound primary windings havinga common terminal forming one connection with a periodic source ofcurrent, said cath odes being connected together and to the other sideof said source, the other terminals of said primary windings beingrespectively connected to said anodes.

2. A frequency changing device comprising a pair of evacuated tubes eachcontaining an anode, a grid and a cathode, a suitable vapor contained ineach tube whereby the current shall be transported by the ions, anauxiliary are for maintaining the cathode in an incandescent state, acommutator for intermittently impressing a negative potential ofconstant value upon said grids; and a: transformer having a singlesecondary winding and a pair of equal and oppositely wound primarywindings having a common terminal forming one OOIIIIGCtlOIl with apzriodic source of current, said cathodes ing connected together and tothe other side of said source, the other terminals of said primarywindings being respectively connected to said anodes.

3. A frequency chan ing device comprising apair of evacuate tubes eachcontainin an anode, a grid and a cathode, a suit-. ab e vapour containedin each tube, whereby the current shall be transported by the ions,

' anod an auxiliary are for maintaining the cathodem an lncandescentstate; means for fiterj;

nately aking and breaking the conneetififi of said grid with a source ofconstant potential which is negative with respect to the cathode and atransformer having a single secondary winding and a pair of equal andoppositely wound primary windings having a common terminal formin oneconnection with a periodic source 0 current, said cathodes beingconnected together and to the other side of said source, the otherterminals of said primary windings being respectively connected to saidanodes.

4. A frequency changin device comprising a pair of evacuated tu es eachcontaining an anode, a grid and a cathode, a vapor contained in eachtube whereby the current shall be transported by the ions, means formaintainin each cathode in an incandescent state, means forintermittently imparting a negative tential of constant value to saidgrlds an a transformer having a single secondary winding and a pair ofequal and oppositely wound primary windings having a common terminalforming one connection with a periodic source of current, said primarywindings each having capacitance, said cathodes being connected togetherand to the other side of said source, the other terminals of saidprimary windings being respectively connected to said anodes.

5. A frequency chan ing device comprismg a pair of evacuate tubes eachcontaining an anode, a grid and a cathode, a vapor contained in eachtube whereby the current shall be transported by the ions, an auxiliaryarc for maintaining the cathode in an incandescent state,-means forintermittently imparting a negative potential of constant value to thegrids; and a transformer havin a single secondary windin and a pair 0equal and oppositely woun primary windings having a common termmal orminone connection with a periodic source 0 current, said primary windingseach havin a condenser connected in parallel therewit said cathodesbeing connected together and to the other side of said source, the otherterminals of said primary wmdlngs being respectively connectedto said 6.A frequency changing device comprismg a transformer having a pair' ofequal and gppositel wound primary windin each unted y arcapacitance;means fii r applying a current, the frequency of which is to be changed,to said primary windings; and rectifying means for alternatelyinterrupting the current flow through said primary windings at anydesired frequency, said transformer alsohaving a secondary windm fromwhich is obtained current at the desired frequency and a grid,'and meanswhereby1 7. A frequency and phase changing de-r vice comprising atransformer having a single primary winding adapted to be con taming avapor whereby the current shall be transported by the ions, means forenergizing said cathodes in a continuous manner, each vacuum tubeserving to connect the common terminal of the first mentionedtransformer to one of the remaining terminals of the primary windin s ofthe second mentioned transformers; an means for successivelyinterrupting the current flow through said. vapor containing tubes atone quarter phase intervals of a desired m cycle frequency, whereby twophase alternating current of m cycles may be obtained from the secondawindings of said second mentioned trans ormers.

8. A frequency and hase changing device comprising a trans ormer havinga single primary winding adapted to be connected to a periodic source ofsingle phase at cycle current, and a pair of equal and oppositely woundsecondary windings having a common terminal; a pair of transformers eachhaving a single secondary windin a pair of equal andv opposite wounprimary windings, each pair of said primary windings have a commonterminal each of which is connected to one of the other terminals of thesecondary winding of the first mentioned transformer; a plurality ofpartial vacuum tubes containing a vapor whereby the current shall betransported by the ions, each comprising an anode, a cathode arc isenabled to excite the cat ode in a continuous manner, each of the saidtubes serving to connect the common terminal of the firstmentioned-transformer to one of the remainin terminals of the primawindings of e second mentioned tran ormers; and means for successivelyinterrupting the current flow through said tubes at one quarter phaseintervals of a desired m cycle frequency, whereby two phase alternatingcurrent of m cycles may be obtained from the secondary windings of saidsecond mentioned transformers.

9. A frequency and fphase changing de-' vice comprising a trans o'rmerhaving a single primary wmding adapted to be connectan auxiliary and,

ed to a periodic source of single phase n cycle current, and a pair ofequal and oppositely wound secondary windings having a common terminal;a pair of transformers each having a single secondary winding and a pairof equal and oppositely Wound primary windings, each pair of saidprimary windings having a common terminal, each of which is connected toone of the other terminals'of the secondary winding of the firstmentioned transformer; a plurality of partial vacuum tubes eachcontaining a vapor whereby the current shall be transported by the ions,an anode, a cathode, a grid, and means for producing an auxiliary arefor constantly maintaining the cathode in the incandescent state, eachof the said tubes servingt'o connect the common terminal of the firstmentioned transformer to one of the remaining terminals of the primarywindings of the second mentioned transformers; and means forsuccessively connecting and disconnecting said grids with a source ofconstant potential negative with respect to the cathodes of said tubesat one quarter phase intervals of a desired m cycle frequency, wherebytwo phase alternating current of m cycles may be obtained from thesecondary windings of said second mentioned transformers.

In testimony that I claim the foregoing as my invention, 1 have signedmy name.

CHARLES LEONARD ARMAND MAURICE LEBLANC.

